1. Field of Invention
The present invention relates generally to drawbars for coupling an implement to a towing vehicle, and more particularly, to a pin retention assembly for swinging drawbars commonly used with agricultural tractors.
2. Description of Related Art
Agricultural tractors and other work machines are commonly used to tow implements behind them for various purposes, including planting, plowing and leveling. Drawbars are commonly incorporated on the back of a tractor to provide a point of attachment for the implement to the tractor. It is important to control the implement so that turning and other desired operations can be readily accomplished. Such drawbars have been designed to allow some swinging movement of the implement relative to the tractor.
At times it is desired to prevent side-to-side movement of the drawbar through the use of drawbar pins. Several devices, such as linchpins, safety clips, cotter pins, bolts, spring roll pins and other forms of latches have been used to limit the inadvertent removal of the drawbar pin. For example, a linchpin may be inserted through a portion of the drawbar pin. Although the afore-mentioned arrangement works well, the use of the linchpin has several drawbacks. First, the linchpin is a non-attached component of the drawbar pin and thus is often lost over the course of time. In agricultural applications, there are often plants and crop debris that can pull the linchpin out of the drawbar pin. Additionally, linchpins require a hole or groove to be drilled in the drawbar pin. Devices such as cotter pins, spring roll pins and bolts traditionally require tools to remove, which sometimes is not desired when quick pin removal in the field is required. In addition, there is nothing to prevent the use of the drawbar pin without the linchpin.